E10 petrol and accidental use

Posted on August 17th, 2021 by GEM Motoring Assist

E10 petrol and accidental use

‘Standard’ 95RON petrol is due to have its bio-ethanol content increased from up to 5% (E5) to up to 10% (E10) from September. If this is news to you, it is worth checking out:


Our 2018 blog that looked at when consultations started about the fuel: https://blog.motoringassist.com/general-motoring/will-new-green-e10-petrol-cost-dear/


You can access a later blog on E10, from earlier this summer: https://blog.motoringassist.com/car-maintenance/oils-and-fluids/e10-unless-you-drive-diesel-or-fully-electric-you-will-be-affected/


Not all cars can run on E10. The main problem is that the increased bio-ethanol content causes corrosion within the fuel system, resulting in expensive mechanical failure.


As the date for E10’s formal UK introduction gets closer, some advice (including that from government) has been circulating that gives you the impression that brimming the tank of an incompatible car with E10 accidentally poses no great problem. We have come across bio-ethanol producers saying that ethanol is innocuous but, after all, they have a vested interest in E10’s adoption. Yet, the advice disagrees with not only various car manufacturers that state E10 is harmful to a car not designed to use it but also independent evidence.


In 2011, ADAC in Germany found that a brand-new high-pressure fuel pump, fitted to an E10 incompatible Vauxhall 2.2-litre Signum, failed after 27,000 kilometres of running on E10. ADAC found that the corrosion attack is triggered after a single misfuelling event, which, notably, becomes unstoppable.


Therefore, GEM echoes ADAC’s advice: only use E10 petrol on cars that are designed to use it. You can look up your car on this list to see if it is compatible: